Data storage
metrics

Use Java Management Extensions (JMX) APIs to collect the metrics exposed by the
various HDFS daemons. For the garbage collection metrics from the NameNode, you can use the
Concurrent Mark Sweep (CMS) GC or configure the Garbage First Garbage Collector
(G1GC).

Using JMX for accessing HDFS metricsYou can access HDFS metrics over Java Management Extensions (JMX) through either the web interface of an HDFS daemon or by directly accessing the JMX remote agent.